SRS 2.3 Crossover and Tweeter Upgrades
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schwarcw
Posts: 7,328
I recently completed a crossover and tweeter upgrade on my SRS 2.3s. Please note these are not the TLs. This is the second crossover upgrade I performed within the last two months. The first upgrade was on my SDA-2s, which was performed by a friend of mine as I didnt feel comfortable doing this myself. I havent used a soldering iron to any degree of experience. However, after watching my friend Bill and playing around a little bit at home, I felt comfortable going at this project on my own. My RD-0194 tweeters were on backorder from Polk and I was getting cabin fever. Additionally, Sonic Craft was having their first ever sale, 20% off everything. So I ordered Sonicaps and Mills resistors. Jeff Glowacki at Sonic Craft has been very helpful to me. So I sent him a copy of the schematic for the 2.3s. Jeff recommended that I by-pass all the capacitors in the tweeter circuit with a 0.1 uF cap. Additionally, the uF values for the capacitors in the tweeter circuit that I ordered were reduced by 0.1 uF in order to maintain the original value specified by Polk. I talked with the rep at the warehouse as advised by Jeff. Since the lower values that I wanted were within the 5% manufacturing tolerance, he pulled the capacitors I wanted and measured each one to get the actual values of the caps. The caps were relabeled to show the actual values. There was no additional charge for this. Here is a summary of the original and replacement parts:
Original Polk Replaced With
(2) 4.4 uF (2) 4.3 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(2) 5.8 uF (2) 5.7 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(4) 12.0 uF (4) 11.9 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(2) 20.0 uF (2) 20.0 uF Gen I
(2) 40.0 uF (4) 20.0 uF Gen I (2 in parallel for 1 40 uF)
(2) 6.2 ohm (2) 6.2 ohm MRA-5
(2) 22.5 ohm (2) 22.0 ohm MRA-5
(4) 33 ohm (4) 33 ohm MRA-5
I also bought 2 stereo sets of Vampire binding posts to replace the Polk originals. I bought the long ones, but the short ones would have worked.
When I removed the passive radiator to access the crossovers, I was pleasantly surprised to see that the 2.3 crossovers had wiring harnesses and pin connectors. This made disassembly very easy since I didnt have to remove all the tweeters and drivers like I had to do for the SDA-2s. I went a little slower on the first board so it took a little longer. Desoldering probably took more time than resoldering the new components, maybe because of my inexperience. Polk manufacturing technicians went wild with the hot glue gun over the boards when they were finished. The big problem was the coils. Although I didnt remove any of the coils, because the glue was piled onto the coils and the surrounding caps and resistors I had to be careful to cut the dried glue with an Exacto knife without slicing through the very fine wire leads from the coil. This enabled the caps/resistors to be removed from the board. I did this before desoldering the components.
My next surprise was examining the polyswitches. I had not seen these prior to this project but I read a lot about these on the Forum posts. What surprised me was how flimsy these things were. I understand the replacements are a little better, but I decided to replace these with a jumper I made with a 14 gauge insulated solid copper wire that I bent into a small U shape.
Installing the new replacement components was not too difficult. The Sonicaps came with very long leads (4) compared to the Solens (2). In some instances I needed every bit of these leads in order to make the bends needed to contort the capacitors to fit this very small board. If I would have used the Solens caps, I would have needed lead extensions in some locations. All of the capacitors and resistors were mounted horizontally. I played with the components to try and find the best fit geometry and orientation. I could have mounted a couple of the vertically. But in the end it would not have afforded me any more board space. I did go off the side of the board in one location. I cut some poly-foam and fit it against the capacitor, resistor and the board to make a physical bridge that I could lay down some hot glue to stabilize these floating components to the board. In a few locations the leads for the caps and resistors were so close that I covered them with some shrink tube. The leads were not actually touching, but I felt more comfortable with a little bit of insulation insurance. I did not shrink the tubes because I wanted to allow some flexibility to move the tube after the soldering was complete.
The first board took me about 4 ½ hours to complete, the second board took me about 3 hours. Everything went back together without a problem. I connected the speakers with the original SL 2000 tweeters (since the RD-0194s were still on back order) and began to listen to see if I could hear some differences. I immediately noticed more defined mid-range and bass, the tweeters were not nearly as harsh and the SDA definition was much more pronounced, maybe more than 180 degrees of sound in certain musical passages. I wouldnt say the change was dramatic, but it wasnt subtle either. It was immediately noticeable. I burned the components in for about 50 or so hours before the tweeters finally arrived. I knew the RD-0194s would soften the HF, the change was definitely noticeable.
Sorry for the long thread. The real message here is that I am a novice at electronics. But reading the Forum, asking for advice and information gave me some confidence to do this on my own. To other newbies out there, if I can do it then you can do it also. Thanks to everyone for your information, guidance and support.
Heres a few pictures of this project:
Original Polk Replaced With
(2) 4.4 uF (2) 4.3 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(2) 5.8 uF (2) 5.7 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(4) 12.0 uF (4) 11.9 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(2) 20.0 uF (2) 20.0 uF Gen I
(2) 40.0 uF (4) 20.0 uF Gen I (2 in parallel for 1 40 uF)
(2) 6.2 ohm (2) 6.2 ohm MRA-5
(2) 22.5 ohm (2) 22.0 ohm MRA-5
(4) 33 ohm (4) 33 ohm MRA-5
I also bought 2 stereo sets of Vampire binding posts to replace the Polk originals. I bought the long ones, but the short ones would have worked.
When I removed the passive radiator to access the crossovers, I was pleasantly surprised to see that the 2.3 crossovers had wiring harnesses and pin connectors. This made disassembly very easy since I didnt have to remove all the tweeters and drivers like I had to do for the SDA-2s. I went a little slower on the first board so it took a little longer. Desoldering probably took more time than resoldering the new components, maybe because of my inexperience. Polk manufacturing technicians went wild with the hot glue gun over the boards when they were finished. The big problem was the coils. Although I didnt remove any of the coils, because the glue was piled onto the coils and the surrounding caps and resistors I had to be careful to cut the dried glue with an Exacto knife without slicing through the very fine wire leads from the coil. This enabled the caps/resistors to be removed from the board. I did this before desoldering the components.
My next surprise was examining the polyswitches. I had not seen these prior to this project but I read a lot about these on the Forum posts. What surprised me was how flimsy these things were. I understand the replacements are a little better, but I decided to replace these with a jumper I made with a 14 gauge insulated solid copper wire that I bent into a small U shape.
Installing the new replacement components was not too difficult. The Sonicaps came with very long leads (4) compared to the Solens (2). In some instances I needed every bit of these leads in order to make the bends needed to contort the capacitors to fit this very small board. If I would have used the Solens caps, I would have needed lead extensions in some locations. All of the capacitors and resistors were mounted horizontally. I played with the components to try and find the best fit geometry and orientation. I could have mounted a couple of the vertically. But in the end it would not have afforded me any more board space. I did go off the side of the board in one location. I cut some poly-foam and fit it against the capacitor, resistor and the board to make a physical bridge that I could lay down some hot glue to stabilize these floating components to the board. In a few locations the leads for the caps and resistors were so close that I covered them with some shrink tube. The leads were not actually touching, but I felt more comfortable with a little bit of insulation insurance. I did not shrink the tubes because I wanted to allow some flexibility to move the tube after the soldering was complete.
The first board took me about 4 ½ hours to complete, the second board took me about 3 hours. Everything went back together without a problem. I connected the speakers with the original SL 2000 tweeters (since the RD-0194s were still on back order) and began to listen to see if I could hear some differences. I immediately noticed more defined mid-range and bass, the tweeters were not nearly as harsh and the SDA definition was much more pronounced, maybe more than 180 degrees of sound in certain musical passages. I wouldnt say the change was dramatic, but it wasnt subtle either. It was immediately noticeable. I burned the components in for about 50 or so hours before the tweeters finally arrived. I knew the RD-0194s would soften the HF, the change was definitely noticeable.
Sorry for the long thread. The real message here is that I am a novice at electronics. But reading the Forum, asking for advice and information gave me some confidence to do this on my own. To other newbies out there, if I can do it then you can do it also. Thanks to everyone for your information, guidance and support.
Heres a few pictures of this project:
Carl
Post edited by schwarcw on
Comments
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I can never get over how HUGE those caps are... BTW- make sure you're driving these with clean power now that the polyswitches are gone. I've never tripped mine, but the first time you do it makes it worth it to have them there....Ludicrous gibs!
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I would highly recommend the 0.1 uF bypass cap instead of the 750 pF. There was a long thread about this sometime in November(?). Stew was the thread initiator.
Stew used the 0.1 uF on his SDA-2B's, I also did the crossovers on my SDA-2's. I also used the Sonicaps on my SDA-2's. They cost more but I think it was worth it. I'm sure the Solen's would do a good job also.
I'm using a Monster 3500 power conditioner, PS Audio power cords and the speakers are being driven by a Halo A21 (250 wpc @ 8 ohms). I don't typically listen above -20 dB. At that level, the 2.3's are singing real nice:D
CarlCarl -
your sda-2's had the pin/blade? I currently have my blade/blade apart. Just put in new silks. I don't have a dam thing behind my drivers on my srs 2's. Two boards at the bottom. One attached to the interconnect blade/blade has 3 electrolytics and the board attached to the speaker terminals has no electrolytics. It has 4 sandbox resistors I guess I'll replace. Does anyone have a schematic for a srs 2 blade/blade? I might be missing something here. All I have is 3 caps and 4 resistors to replace. The other caps aren't electrolytic and read good on a cap checker.
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Check out this thread (#3) for a schematic of the SRS 2 courtesy of Scompracer:
http://www.polkaudio.com/forums/showthread.php?t=35863&highlight=srs
CarlCarl -
Yup, the second one is it. Not much there. juice suckin sucker. cheap replacement parts tho!!!!! I LIKE!!!!!!!! Thanks very much.
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Carl, is that a 130 microfarad cap there on bottom?
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fshan wrote:Carl, is that a 130 microfarad cap there on bottom?
No, I don't have anything that large. The caps are:
(2) 4.4 uF (2) 4.3 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(2) 5.8 uF (2) 5.7 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(4) 12.0 uF (4) 11.9 uF Gen I plus (2) 0.1 uF Gen II (200 volt)
(2) 20.0 uF (2) 20.0 uF Gen I
(2) 40.0 uF (4) 20.0 uF Gen I (2 in parallel for 1 40 uF)
The one on the bottom that I think you are looking at is a 4.3 uF.Carl
